Alloys for addition to iron and steel



Patented 6, 1938 hurrah sT 'ras rarest orries No mrawinn. AppilicaflnnApril 25, 1000,, Burial No. itlliinmll mins.

This invention relates to an alloy containing silicon, titanium,zirconium, aluminum and iron, and especially to an alloy suitable foradditions to molten iron and steel for the purpose of obtain- 'ing amore sound, dense and clean metal when such steel or iron solidifies.

The present application is a continuation-in-= part of my copendingapplication, Ser. No. 128,- 231, filed February 27, 1937.

, The use of term-silicon, term-titanium, ierro zirconium, aluminum,farm-aluminum, iron-sill con-zirconium, arid iron-silicon-titanium torthe purpose of scavenging molten steel and iron is very well-known andthese alloys are more or less generally employed in iron and steelmanufacturing practice. Their use, however, is accompanied by verymarked deficiencies so that, while they ireethe molten metal ofimpurities, such as iron oxide and iron nitride by chemically reacting2G with these compounds, the products: iron-silicate, alumina, titaniumcyanonitrides, and zirconium cyanonitrides, remain entrapped in themetal, thereby imparting to it several objectionable qualities. Theamount of non-metallics remaining entrapped in the metal is not alwaysthe same- Therefore, iron and steel alloys are obtained which havevarying physical qualities, such as ductility, although of the samechemical composition.

80 I have discovered that the combination 0! all four elements-silicon,titanium, zirconium and aluminum-with iron, in proper proportions, pro,duces an alloy which when added to molten iron and steel reacts withgaseous, and other impurities in the molten metals to form reactionproducts which more readily coagulate and separate from the molten ironor steel. My alloy is readily soluble in molten iron or steel and ismore eflective and economical than alloys containing one or two of theelements silicon, titanium, zirconium, aluminum alone or in combinationwith iron.

My alloy not only acts as a' scavenger in molten iron and steel, 1. e.,removes the-various impurities in the molten metal, but also serves tocontrol the grain size 01 the treated product.

While my alloy is composed of silicon, titanium, zirconium, alumin andiron and is substantially free from carbon, there may be present smallpercentages of other elements incidental to the method at production orin the raw materials (631i. lid- 50) used. For example, the chemicalcomposition of one melt of this alloy which may be considered typical inrespect to the presence of the other metals, is:

Per cent 5 fiilicon 31.20 Titanium 11.70 Zirconium 9.75 Aluminum 0.50Manganese 0.07 10 Carbon 0.06 liron Balance This alloy is substantiallyfree from carbon, but the carbon content may vary up to a maximum oiabout 2.0% or even up to 10.0%, dependmg upon the method of manufactureand intended use. In many cases, I prefer to have the carbon below0.15%.

The improved composition of my present invention consists oi. an alloywith a minimum amount of carbon so as to be substantially free fromcarbon and contains about 10% to 50% silicon, preferably about 10% to45% silicon, about 5% to 15% or titanium, about 5% to 15% or 25%zirconium, andabout 5% to 15% or 25% alumi- 25 num. In no case, however,does the sum 01 the silicon, titanium, zirconium and aluminum exceed90%. The percentage of silicon is at least equal to or greater than thepercentage of either the titanium, the zirconium or the aluminum. Theremainder of the alloy is principally iron, although usual impurities orsmall amounts of other alloying elements may be present.

While I have described my alloy in its preferred composition, it is tobe understood that the in- 3 vention is not so limited, but may beotherwise embodied within the scope of the following claims.

I claim:

1. An alloy for addition to iron and steel, containing about 10% tosilicon, about 5% to 25% titanium, about 5% to 25% zirconium, about 5%to 25% aluminum, the sum of the silicon, titanium, zirconium andaluminum not exceeding and not over about 10.0% carbon, the remainderbeing principally iron.

2. An alloy for addition to iron and steel, con--' taining about 10% to50% silicon, about 5% to 25% titanium, about 5% to 25%. zirconium, about5% to 25% aluminum, the sum of the silicon,

' titanium, zirconium and aluminum not exceeding 90%, and not over about2.0% carbon, the remainder being principally iron.

3. An alloy for addition to iron and steel, containing about 10% to 50%silicon. about 5% to 25% titanium, about 5% to 25% zirconium, about 5%to 25% aluminum, the sum of the silicon. titanium, zirconium andaluminum not exceeding 10 90%, the percentage of silicon being not lessthan

